Quasi-Contractions on Kreĭn Spaces View Full Text


Ontology type: schema:Chapter     


Chapter Info

DATE

1993

AUTHORS

Aurelian Gheondea

ABSTRACT

A quasi-contraction, acting between Kreĭn spaces, is a linear bounded operator which is contractive when restricted to some subspace of finite codimension. If, in addition, the same property is satisfied by the adjoint of the operator, then it is called a double quasi-contraction. This paper is devoted to the investigation of basic properties of quasi-contractions and double quasi-contractions. Among others, we prove that the compression of a quasi-contraction (double quasi-contraction) to maximal uniformly negative subspaces is a semi-Fredholm operator (respectively, Fredholm operator) and we give a formula to compute its index. A spectral characterization of double quasi-contractions within the class of quasi-contractions is also obtained. More... »

PAGES

123-148

References to SciGraph publications

  • 1974. Indefinite Inner Product Spaces in NONE
  • 1990. Extension Theorems for Contraction Operators on Kreĭn Spaces in EXTENSION AND INTERPOLATION OF LINEAR OPERATORS AND MATRIX FUNCTIONS
  • 1982. Spectral functions of definitizable operators in Krein spaces in FUNCTIONAL ANALYSIS
  • Book

    TITLE

    Operator Extensions, Interpolation of Functions and Related Topics

    ISBN

    978-3-0348-9687-0
    978-3-0348-8575-1

    Identifiers

    URI

    http://scigraph.springernature.com/pub.10.1007/978-3-0348-8575-1_7

    DOI

    http://dx.doi.org/10.1007/978-3-0348-8575-1_7

    DIMENSIONS

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